"Oysters can be eaten in addition to shells and offal can not be eaten, the other can be eaten. Oyster shells are certainly not eaten, oysters are best not to eat offal, because oysters in the viscera of the group is easy to hide heavy metals and other seaweed or pollutants, in the muscle of the highest content of heavy metals. Therefore, when eating oysters, look at the color of the muscle. The slightly blackened part of the meat is mostly offal mass, and this part should not be eaten. Because in the big hotel guests are more, so no staff in the cooking